i6 THE PHILOSOPHY 



young of the viviparous are hatched in the uterus previous 

 to their exckifion. 



Many ftriking anologies fubfift between the eggs of ani- 

 mals and the feeds of plants. When placed in proper cir- 

 cumftances, they both produce young every way iimilar to the 

 parents. To accompli fh this wonderful efFeifV, the egg re- 

 quires impregnation and heat. Moifture, warmth, and foil, 

 or fome fimilar matrix, are neceflary for the exclufion of the 

 young plant. This analogy has been extended much farther 

 by Linnaeus, and other fbpporters of the fexual fyftem of 

 plants. They maintain, that impregnation is equally indif- 

 penfable to the vegetation of the feed, as to the fertility of 

 the egg. But, as this doclrine will be difculTed when we 

 come to treat of fexes in general, we fliall here difmifs it 

 without farther remark. 



Eggs are not only analogous to feeds, in their general def- 

 tination of reproducing individuals, and continuing the fpe- 

 cies, but there is a great iimilarity in the flructure and ufes 

 of their refpecSlive organs. '^ 



The internal parts of the egg are covered with a cruft or 

 fhell, and two membranes. Befide thefe, the yoke is includ- 

 ed in a feparate membrane. When the two firft membranes 

 are removed, the white appears every way invefting the yoke. 

 In the white, or rather on the membrane of the yoke, a fmall 

 cicatrice is difcernible, in the centre of which is the punElum 

 fallens^ or embryo of the future animal. After two or three 

 days incubation, this puncliim /aliens becomes red, and fhoots 

 out blood -veflels, which are difperfed through the yoke, in 

 the fame manner as the velTels of a foetus are diftributed 

 over the placent^. 



A feed is likewife covered with a fhell, or cruftaceous 

 membrane. Another membrane invefls the whole ker- 

 nel, or pulpy lobes of the feed. Each lobe, like the 

 yoke of the egg^ \% involved in a feparate membrane. In 



